1. Field of the Invention
The present invention relates to binoculars.
2. Descripton of the Related Art
Chromatic filters are known to be used in optical instruments in order to improve the perceptibility of certain objects.
A filter that is described in DE 39 09 434 C2 exhibits, besides a transmissivity range situated within the red wavelength region, an additional transmissivity band within a wavelength range between 400 nm and 525 nm which has its maximum at 470 nm. At shorter wavelengths in comparison with the wavelengths of chlorophyll fluorescence this additional transmissivity band performs two functions: on the one hand, it serves to make the surroundings—that is to say, objects and living organisms that do not contain chlorophyll—appear to the observer in colours that are as natural as possible; on the other hand, the additional transmissivity band takes account of the physiological peculiarity of the human eye of being able, in a dark environment, to be brought by light radiation within a shorter wavelength range into a state of higher sensitivity which is effective in respect of the entire wavelength region of visible light—that is to say, also in respect of red light.